Excitabletom
Member
This has been the snowmobile season from hell! I bought a very nice looking 97 SX 700 this fall with 6200 miles. Being an experienced snowmobiler, I checked it out real well, or so I thought. I took it to a mechanic pre-seaon to have the carbs cleaned and synronized.
While it was there, I asked him to give it a check-over. The W bracket was broke and most of the rear suspension needed new bearings, bushing, slides, etc. That was expensive, but at least I will have a dependable sled, right?
First ride I had overheat issues. I took it back and had the water pump mechanical seal replaced. Now, 200 miles later, this:
Symptoms: The sled was always harder to start than I'm used to with Yamahas, especially when the engine was warm. I had to hold the throttle wide open to start a warm engine.
Next, while riding today, I noticed that once I let off from high speeds, the motor was real boggy to get the rpm's and speed back up. I thought I better rebuild the secondary soon.
A few miles later at 50 mph, the motor just shut-off. I knew I was in trouble, but I tried to slowly pull the starter rope to feel what happened and the motor was stuck hard. I checked all three plugs and they looked good (the middle one had a stripe on the elctrode, but still mostly good looking.) I then tried to turn the motor by hand at the primary clutch and it turned about 4/5 of the way "normal", then got hard to turn. I could muscle it past the tight spot for another turn, then tight again. We towed it out of the woods.
My buddy and I have a strong idea, but I want to hear your ideas first. Did I mention the wife is pissed at blowing a second snowmobile motor this season!?!
While it was there, I asked him to give it a check-over. The W bracket was broke and most of the rear suspension needed new bearings, bushing, slides, etc. That was expensive, but at least I will have a dependable sled, right?
First ride I had overheat issues. I took it back and had the water pump mechanical seal replaced. Now, 200 miles later, this:
Symptoms: The sled was always harder to start than I'm used to with Yamahas, especially when the engine was warm. I had to hold the throttle wide open to start a warm engine.
Next, while riding today, I noticed that once I let off from high speeds, the motor was real boggy to get the rpm's and speed back up. I thought I better rebuild the secondary soon.
A few miles later at 50 mph, the motor just shut-off. I knew I was in trouble, but I tried to slowly pull the starter rope to feel what happened and the motor was stuck hard. I checked all three plugs and they looked good (the middle one had a stripe on the elctrode, but still mostly good looking.) I then tried to turn the motor by hand at the primary clutch and it turned about 4/5 of the way "normal", then got hard to turn. I could muscle it past the tight spot for another turn, then tight again. We towed it out of the woods.
My buddy and I have a strong idea, but I want to hear your ideas first. Did I mention the wife is pissed at blowing a second snowmobile motor this season!?!
YamahaSXR700
Member
could be a crank bearing or connecting rod bearing
Ditto with above
Not fogged properly at the end of the season would be my guess
Not fogged properly at the end of the season would be my guess
Excitabletom
Member
That was our guess as well. What type of potential damage am I looking at? What does this type of failure usually cause damage-wise? Crank destroyed? Cases damaged? I know we are just speculating, but I want to know what to expect or need to look for.
I hate snowmobiles. Today anyway...
I hate snowmobiles. Today anyway...
Sometimes it is as simple as bearings others it reguires crank and or rods. Need to just get it apart and see what went wrong. Maxdlx
My money would be on the mag side bearings. If it is get a '98 mag side bearing and collar. This was Yamaha's fix for thos potential failure point.
teamblue02SRx
New member
just curios about the foging , what is the proper way so i dont do this
yamahauler4
New member
After a high run and rpms banging off a 3500 ceiling, it was my TORS. Disabled, problem gone.
not fogging the motor caused your problem, fogging it is as easy as spray fogging oil in air box while running for a couple minutes. just enough at a time to about stahl it, then let it breath and do it again. Maxdlx